Apparatus for investing dental casting patterns



y 1935- Y D. w. PHILLIPS 2,006,652

APPARATUS FOR INVESTING DENTAL CASTING PATTERNS Filed April 29, 1952 3Sheets-Sheet 1 Zzy-/ a I134 Q //a" /2 if jdado/Wfi/A 'M I y 1935- D. w. PHILLIPS v ,0

APPARATUS FOR INVESTING DENTAL CASTING PATTERNS Filed April 29, 1932 3 Sheets-Sheet 2 4 v-----li I I I "nun", I "r July 2, 1935. 0. w. PHILLIPS 2,005,652

APPARATUS FOR INVESTING DENTAL CASTING PATTERNS Filed April 29, 1952 s Sheets-Sheet s izyi X9 24 W \27 29 /Z6 25 g Patented July 2, 1935 UNITED ESTATES PATENT v OFFICE APPARATUS FOR INVESTING DENTAL CASTING PATTERNS 10 Claims.

This invention relates to the preparation of dental castings and particularly to an improved method and apparatus for investing the casting pattern in a manner which will thoroughly distribute a heavy mix of investment over the surface of the pattern, thereby enabling the production of very smooth castings.

In my co-pending application, Serial No. 584,089, filed December 31, 1931, I have disclosed a method and apparatus whereby the casting pattern from which the casting is formed is maintained in vibratory condition during the period in which it is being embedded in the mass of investment. As pointed out in this prior application, the effect of maintaining the pattern under a condition of vibration while it is being introduced into investment, is to effect complete and perfect distribution of investment over the pattern without permitting formation of air pockets between the pattern surfaces and the adjacent body of investment. In accordance with the practice as disclosed in my prior application, the pattern Was arranged to be movably supported above the investment container, means being provided for automatically raising and lowering the pattern relative tothe container, there also being provided means for vibrating the pattern during its movement to and from the container. I

One of the objects of the present invention is to provide improved means for raising and lowering the pattern relative to the investment container.

Another object of the invention is to provide,

in combination with means for effecting vibration of the pattern, additional means operating independently of said pattern vibrating means for imparting vibratory movement to the investment container and the bodyof the investment contained therein.

Another object of the invention is to provide a method of operation and an eflicient apparatus whereby excess moisture contained in the investment after the pattern has become embedded therein may be expelled from the mass by the application of pressure thereto, there being provided means for absorbing moisture which has been thus pressed from the investment.

Other objects and advantages of the invention will appear from the following detailed description, which, taken in connection with the accompanying drawings, discloses a preferred embodiment thereof.

Referring to the drawings: Fig. 1 is a side elevational view of the improved apparatus provided for investing a casting pattern;

Fig. 2 is a front elevational view of the investing apparatus;

Fig. 3 is a top plan view of the same; 5 Fig. 4 is a fragmentary section through the apparatus taken on line 44 of Fig. 1, the view showing the cam mechanism provided for raising and lowering the pattern-supporting assemy;

Fig. 5 is a vertical section through the apparatus taken on line 55 of Fig. 1, the view showing the switch mechanism which controls the pattern vibrating means;

Fig. 6 is a horizontal section through the ap-' 15 paratus taken on line 6-6 of Fig. 5, the view showing details of the drive motor which operates the lifting cam;

Fig. 7 is a vertical section taken on line 1--1 of Fig. 5, the view showing further details of 20 the drive motor and the switch mechanism which controls the pattern vibrating means;

Fig. 8 is a detail of the manually operated motor wind-up device, the View being taken on line 8-8 of Fig. '7; j

Fig. 9 is a detail section through the platform for supporting the investment container and the means-for vibrating said platform; and

Fig. 10 is a schematic wiring diagram showing the circuits provided for energizing the vibrators which are associated with the patternsupporting means and the platform which supports the investment container.

Referring to the drawings and particularly to Figs. 1-3, the numeral l5 designatesa base upon which is supported a box-shaped housing indicated generally by the numeral l6 and consisting of side walls l1, end walls l8, and a top wall l9. Both the base l5 and the housing l6 are preferably made of sheet metal, the housing being removably secured to the base by a series of screws 2| which engage brackets 22 carried by the base.

Referring to Figs. 2 and 9, a tubular investment container 22 is adapted to be supported on the top wall of the housing at the forward end thereof, said top Well being struck downwardly to provide a well or cavity for receiving said container, the side walls of this cavity be-, ing indicated at 23, the bottom wall thereof being indicated at 24. Container 22 is not supported directly upon bottom wall 24, a floating platform 25 being provided for supporting the lower end thereof, said platform being supported for free movement on wall 24 by means of a and forcing excess water therefrom.

depending plug portion 26 which extends from the under face of platform 25 through an opening 21 formed in wall 24. The depending plug portion 26 constitutes the armature of an electrical vibrator, the coil of which is indicated at 28, said coil being wound about a core 29 which is secured by a bracket 3| to front wall I8 of the housing. In the'embodiment shown this platform vibrating means is arranged to be operated by alternating current which is supplied to coil 28 through transformer 32 (Fig. 7) which is mounted on the base 15. It will be apparent that when coil 28 is energized the rapid alterations of the current will provide successive attractions and repulsions of core 26, thereby imparting rapid vibrations to platform 25 and the investment container 22 which is supported thereon.

Continuing the reference to Fig. 9, container 22, in accordance with the usual practice, is adapted to receive a mass of investment 33. The lower end of the container is closed by a rubber end cap which affords a water-tight seal. A casting pattern, indicated at 35, .is supported in'the investment in the usual manner on a sprue 36 which is removably secured in the lower end of a crucible-forming holder 31,- the cone-shaped crucible forming portion 38 of which depends into the mass of investment 33 and the supporting rim portion 39 of which is 41 which engages against the under face of rubber cap 34 and which is adapted to be received in the lower end of the investment container 22. It will be apparent that when a downward pressure is applied to the container 22 and the pattern-supporting.assembly positioned thereon, plunger 29 and the overlying portion of cap 34 will be forced upwardly into the lower end of the container, thereby compressing the mass, of investment In order to quickly remove this water from the investment, holder 31 is formed of water absorbent material such as plaster of Paris, absorbent paper, or the like. An absorbent sprue-holder .which is particularly well adapted for this purpose is shown in my co-pending application Serial No. 596,447,'filed March 3, 1932. A description of the means provided for producing downward pressure on the investment container will not be given until after the means for raising and lowering the pattern-supporting assembly has been described. 7

By vibrating the mass of investment which surrounds the pattern I am able to completely distribute the investment over the pattern surface, thereby avoiding the danger of formation of air bubbles or pockets between the pattern surface and the contacting portion of the investment. Also, by compressing the mass of investment to force excess water therefrom I am able to increase the density of the mass and reduce the time required for the initial set. Inasmuch as the compressed investment contains less moisture for unit volume, it has greater crushing strength and also greater thervestment to remove water therefrom are, therefore, both important in the successful production of smooth castings. It is to be understood, however, that these steps need not be necessarily used in conjunction with one another, since either one has its effect independently of the other. Vibration, in conjunction with pressure and absorption, expedites the flow of investment about the pattern without causing distortion of the pattern as the investment is compressed, and also promotes absorption of moisture from and condensation of the investment.

Referring to Figs. 1 and 7, the pattern-supporting assembly, which comprises holder 31 and sprue '36,.is arranged to be raised and lowered on container 22. To this end said assembly is adapted to be removably supported on the base by means of a tubular arm 42 whichyis pivotally connected at one end to. a hinge 43,

the latter in turn being secured to a plate 44 which is supported by vertical frame pieces 45 and 46. As shown in Fig. 7, the top wall ll! of the housing is struck upwardly, as indicated at 41, the upwardly projecting portion being provided with .an opening 48 for receiving arm 42.

The free end of arm 42 carries a plate 49 which is provided at its opposite sides with springpressed clips (Fig. 2) which are provided at their lower ends with hook members 52 which engage under the rim portions 39 of the sprue holder to firmly hold the latter against the under face of plate 49. In order to release the holder from clips 5|, it is merelynecessary for the operator to press" saidclips inwardly to swing jaws 52 clear of rim portion 39. When the holder is in clamped position on plate 49 it may be raised and lowered relative to container 22 by merely swinging arm 42 about its point of pivotal connection with hinge 43. The free end of arm 42 carries a vibrator 53 which is bolted to the upper face of plate 49. This vibratormay be of any preferred form and is not shown in detail. .In the embodiment shown the vibrator is supplied with current from the transformer 32. One side of the line is conducted to the coils of the vibrator through a wire 54 which is housed within arm 42. The other side of the line is grounded on the frame. Vibrations induced by vibrator 53 are mechanically transmitted through plate 49 and holder 31 to the pattern. As disclosed in my prior application, Serial No. 584,089, I have found that by vibrating the pattern while it is being inserted into the mass of investment I am able to reduce the tendency toward the formation of air pockets between the surface of the pattern and the contacting mass of investment.

As pointed out in said' prior application, the

preferred procedure is to vibrate thepattern down into the'investment, to then remove the pattern from the investment while maintaining it in a state of continuous vibration, and finallyreinserting the pattern in the investment, after which vibration is discontinued.

The improved means provided for pivoting wall IS; a cam 51 mounted on a shaft 58, the latter being supported between a pair of vertical frame plates 59 and 6|; a follower arm 62 pivotally supported at 63 to the frame and pro vided at its free end with a cam roller 64 for engaging the face of cam 51, said arm being also pivotally connected at 65 to lifting member 55; a spring-actuated motor for driving shaft 58, said motor including a main spring 66 mounted on shaft 58 and a train of timing gears, indicated generally at 61; and a manually operable wind-up device 68 for turning shaft 58 against the tension of spring 66.

Any suitable form of spring motor may be employed for turning shaft 58 and cam 51 and this mechanism will therefore only be described in sufiicient detail to give an understanding of its operation in connection with cam 51. The main spring 66 is anchored at one end to shaft 58, the opposite end thereof being anchored to a pin 69 carried by the frame. One end of shaft 58 carries a spur gear 1| which meshes with a vertically disposed toothed rack 12, the latter being adapted to be pushed downwardly against the tension of spring 66 by means of an arm 13 which projects through the side wall of the housing and which is provided at its outer end with a hand piece 14. Arm 13 is secured to a vertically disposed channel-shaped bracket lfll, slidably supported on a vertically disposed rod I92 which is supported between base l5 and plate 44, the opposite end portions 183 and I94 of said bracket being apertured to receive said rod I92. A forked member I is supported on bracket [0! and engages a laterally projecting stud I65 secured to the lower end of rack 12, thereby providing an operative connection between said rack and bracket I8! which carries arm 13. The ratio of the gear wheel 1| to rack 12 is such that one full downward movement of rack 12 will turn shaft 58 and cam 51 through approximately one complete revolution, the direction of turning of said cam 51 during the wind-up operation being in a counter-clockwise direction, viewing Fig. 4. In the position of cam 51, as shown in Fig. 4, rack 12 will be at the end of its up-stroke, which position represents the point at which the spring motor ceases tofunction.

The timing mechanism which regulates the turning of shaft 58 comprises: a spur wheel 15 carried by shaft 58; a pendulum 16 supported between plates 59 and BI on a shaft 11; and a series of intermeshing gears 18, 19, 89, BI and 92 providing connection between spur wheel 15 on shaft 58 and pendulum-supporting shaft 11.

The lower end of pendulum 16 connects through a spring 83 with a weight wheel 84. An adjusting mechanism, indicated generally by the numeral 85, is provided for raising and lowering pendulum 16 to regulate the timing of of the gear train. By setting this adjusting mechanism, the time required for rack 12 to be moved upwardly through a complete stroke may be regulated, thereby, in turn, regulating the time required for cam 51 to turn through one operative cycle.

Referring particularly to Fig. 4, cam 51 is so shaped that it will produce the following cycle of movements of the pattern relative to the investment container 22: (l) a very gradual lowering of the pattern into the investment, this being accomplished by the portion 86 of the cam; (2) A gradual removal of the pattern from the investment, this being accomplished by the portion 81 of the cam, and this operation being followed by a period in which the pattern is held removed from the investment, this latter function being accomplished by portion 88 of the cam; (3) A second lowering of the pattern into the investment, this being effected by the portion 89 of the cam; and finally (4) .A second raising and lowering of the pattern which is accomplished by portion 9| of the cam, this lastinentioned operation resulting in the positioning of roller 64 as shown in Fig. 4, in which position the sprew holder 31 rests flush on the top of container 22. This operative cycle of cam 51, which represents slightly less than one complete turn of said cam, is accomplished during one full return stroke of wind-up rack 12, which, as previously stated, is so geared to shaft 58 as to produce exactly the desired amount of turning of cam 51 during its return or up-stroke. This arrangement is particularly convenient since it is merely necessary for the operator to push downwardly on arm 13 to carry rack 12 to the limit of its down stroke, and upon releasing said arm the motor will automatically operate to turn the cam 51 through exactly the portion of a revolution required to accomplish the aforementioned cycle of movements for the pattern.

The upper end of lifting member 55 is provided with a roller 92 which engages against arm 42 to reduce the friction between these parts. When supporting arm 42 is removed from the upper end of lifting member 55, the latter is thrown upwardly to carry cam roller 64 away from cam 51, this being accomplished by a spring 93 which engages against the lower edge of follower member 62. Since arm 42 is ordinarily removed from lifting member 55 when the machine is not in operation, roller 94 will be normally out of contact with cam 51, so that during the wind-up operation the parts 55, 62, and 64 do not follow the movements of said cam.

It will be noted from Fig. 1 that the pattern supporting arm 42 is off-set upwardly, as indicated at 94. The purpose of providing this off-set is to insure that pattern 35 will be approximately in line with the axis of the main portion of arm 42. It will be noted from Fig. 9 that the container 22 is positioned in a well or cavity in the top wall of the housing and that the pattern, when completely embedded, is posiioned fairly near the base of the container. By off-setting arm 42 in the manner shown, the pattern is so supported that it will move along the vertical portion of its arc of swing as it clears the upper edge of container 22. The arrangement thus insures that there will be no likelihood of the pattern striking the upper edge of the container as it is removed from or inserted into the mass of investment.

The means provided for producing downward pressure on the investment container 22 and sprue holder 31 comprises an arm 95 (Fig. 4) which is carried on the upper end of a rod 96, the latter extending through a bearing 91 which is mounted in top wall IQ of the base housing. Rod 96 is urged downwardly by a coil spring 93 which is connected at one end to the lower end of rod 96, the other end thereof being secured to frame plate 46. One end of arm 95 is provided with a finger loop 99 which may be engaged by the operator to raise said arm upwardly' against the tension of spring 98. The

other end of arm 95 projects laterally from rod 96 a distance suflicient to carry it over supporting arm 42 when the arm is turned to the position shown in Figs. 1, 3, and 4, in which position'it pulls downwardly on arm 42, thereby producing downward pressure on the patternsupporting assembly and container 22. The downward pressure thus applied to said assembly and container compresses the mass of investment to expel water therefrom in the manner already described. 7 Means is provided for' automatically startin and stopping vibration of the pattern-vibrating means 53 in accordance with the movements of supporting arm 42. Referring to Figs. 5, 6, and 7, a vertically disposed switch control member I01 is slidably supported on rod I02, the laterally bent end portions I08 and I09 of member I01 being apertured to receive said rod I02. A spring switch arm III secured to the base I is adapted to be engaged by a second switch arm 2 which is secured to member I01. Arms III and 2am connected in circuit with the coils of the pattern vibrating mechanisms 53, so that when brought in contact with one another they complete the circuit to said coils to start vibration of the pattern. Member I01 which carries switch arm H2, is yieldingly connected to bracket IN by means of a coil spring H3 which is disposed on rod I02 andwhich engages at its lower end against a collar II4 supported on the portion I04 of bracket IOI. 'A collar I I5 is interposed between the portions I04 and I09 of members IOI and I01, respectively. When rack 12 is in the raised position, bracket IOI will also be raised since it is supported from rack 12 by forked member I05. Switch control member I01 will likewise be held in; raised position by coil spring II 3 which engages a collar I I6 which is carried on the under face of the portion I08 of member I01. When the operator presses downwardly on finger piece 14 to effect wind-up of the motor, bracket II" is moved downwardly and in turn carries switch control member I01 downwardly, the movement of the latter bringing switch arm II2 into engagement with switch arm I I I to complete the circuit to the coils of the vibrating means 53 when finger piece 14 has been moved down sufficiently to complete the wind-up stroke of rack 12. As member I01 reaches the end of its downward stroke it is latched in place by a lever II1 (Fig. 8) which is pivoted at II8 to-frame piece 59, the lower end II9 of lever Il1 being adapted to engage over a lateral projection I2I carried by the end portion I09 of member I01. Lever H1 is urged in a counter-clockwise direction, viewing Fig. 8, by a spring I22 which bears on an upper edge edge portion of the lever. As soon as member I01 reaches its lowermost position, lever II1 snaps over projection I2I and holds member I01.

in switch-closing position. As rack 12 approaches the end of its active stroke, lever H1 is thrown to release switch control member I01, this being effected by one arm of forked member I05 which moves upwardly against a lug I23 carried by the upper end of lever I I1. Upon being thus released, member I01 is snapped upwardly by spring II3 to produce quick opening of switch III, H2. The circuit to the patternvibrating mechanism 53 is thus automatically made and broken in accordance with the movements of the motor wind-up device which in turn controls the movements of supporting arm 42.

In addition to the switch II I, II2 which automatically controls the operation of pattern-vi:

brating means 53, there is provided a manually controlled switch I24, by means of which the circuit to this mechanism may be controlled independently of switch III, II2. A second'manually controlled switch I25 is provided for opening and closing the circuit to the coil 28 of the platform vibrating mechanism.. The relation of these several switches is shown in the wiring diagram of Fig. 10. In this figure the opposite sides of the main line supply circuit are indi-- cated by the wires I26'and I21. The circuits for the pattern vibrating mechanism 53 and the coil 28 of the platform vibrating mechanism are independent of one another, as shown, the former being controlled either by the automatic switch mechanism III, H2 or the manuallycontrolled switch I24, and the latter being controlled exclusively by switch I25. the circuit arrangement might be such as toalso provide for automatic control of the platform vibrating means in accordance with the movements of pattern-supporting arm. 42.

It is believed that a brief statement of the operation will aid to a clearer understanding of the invention. Assuming that the pattern-- supporting arm 42 is swung upwardly to inactive position, the operator secures sprue holder 31 between clips 5I and places the investment container 22, into which the desired amount of investment has been preliminarily introduced, on platform 25. The thickness of rubber end cap 34 is such that until downward pressure is applied to container 22 it will remain. flush across the lower end of said container. The spring motor is then wound up by pushing downwardly on finger-piece 14 which carries switch arm II2 into contact with switch arm III to complete the circuit to the pattern-vibrating mechanism 53. This wind-up operation also pivots cam 51 (Fig. 4) in a counter-clockwise direction through nearly one complete revolution to position the leading edge of the portion 86 of said cam below roller 64. Having preliminarily positioned the parts, the operator lowers supporting arm 42 onto lifting member 55 and at the same time removes his finger .from finger-piece 14, thereby releasing the wind-up mechanism and starting operation of the actuating motor. The weight of arm 42 and the pattern-supporting assembly carried thereby holds cam roller 64 against the face of cam 51, causing said roller to follow the surface of cam 51, thereby producing successive up-and-down movements of arm 42.

When the sprue holder finally comes to rest on the top of container 22, switch control member I01 (Fig. 7) is automatically released and opens the circuit to the pattern-vibrating mechanism 53. Vibration of the supporting platform 25 may be continued and discontinued as desired by operation of switch I25. When the sprue holder finally becomes seated on the investment container, the operator may quickly swing arm- 95 over supporting arm 42 to produce downward pressure on the latter, which in turn causes. downward pressure on the investment container, thereby forcing the plunger portion M of platform 25 upwardly against cap 34. The compression of the investment thus produced expels water from the investment and this is absorbed by the holder 31 to produce quick initial setting of the mass. During the period in which pressure is applied to the mass, vibration of either the, pattern or the mass of investment, or both, may be continued and discontinued as desired by properlymanipulating control switches I24 If preferred,

- and l 25'. If preferred, the operator may dispense with the use of pressure and absorption, in

which case it is, of course, still possible to use the vibrating mechanisms by properly positioning switches I24 and I25. Also, if desired, the

operator may dispense with the use of pressure, and rely solely upon the absorptive capacity of the sprue holder as a means for extracting water from the investment to give quick initial setting. After the investing operation has been completed the pattern-supporting assembly is released by compressing clips 51, whereupon arm 42 may be swung upwardly to allow the invest ment container and the pattern-supporting assembly to be removed from the base.

.L'Ihe foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, but the appended claims should be construed as broadly as permissible in View of the prior art.

What I regard as new and desire to secure by Letters Patent is:

1. Apparatus for investing a casting pattern comprising: a base having a platform for receiving an investment container; an arm pivotally supported at one end on the base; means mounted on the free end of said arm for engaging and holding a pattern-supporting assembly: and means for moving said arm about its point of pivotal upp rt, whereby to a s and lower said assembly relative to the container, said means including a vertically movable lifting member positioned to engage said arm intermediate the ends thereof, a motor, a cam adapted to be driven by said motor, and a follower member affording operative connection between said cam and said lifting member.

2. Apparatus for investing a casting pattern comprising: a base having a platform for receiving an investment container; an arm pivotally supported at one end on the base; means mounted on the free end of said arm for en gaging and holding a pattern-supporting assembly; and means for moving said arm about its point of pivotal support, whereby to raise and lower said assembly relative to the container, said means including a vertically movable lifting member positioned to engage said arm intermediate the ends thereof, a motor, a cam adapted to be driven by said m tor, a i lower member affording operative connection between said cam and the lifting member, and a spring for holding said follower member away from the cam when said arm is removed from the lifting member.

3. Apparatus for investing a casting pattern comprising: a base having a platform for receiving an investment container; an arm pivotally supported at one end on the base; means mounted on the free end of said arm for engaging and holding a pattern-supporting assembly; and means for moving said arm about its point of pivotal support, whereby to raise and lower said assembly relative to the container, said means including a vertically movable lifting, member P ed to engage said arm intermediate the ends thereof, a spring-actuated, motor including a manually-operable Wind-up device, a cam adapted to be driven by said motor, and a follower member affording operative connection between said cam and the lifting member.

4. Apparatus for investing a casting pattern comprising: a base having a platform for receiving an investment container; an 'arm'pivotally supported atone end on the base; means mounted on the free end of said arm for. engaging and holding a pattern supporting assembly;

- means, including a spring-actuated motor and at.

manually-operable wind-up device, for moving said arm about its point of pivotal support, whereby to raise and lower said assembly relative to the container; and electrically operated means mounted on said arm for imparting vibraa tory movement to the pattern, said means including an energizing circuit having a switch adapted to be closed by movement of said windup device to actuating position, and means for automatically opening said switch when said '5 wind-up device has tion. 7 y i 5. Apparatus for investing a casting pattern comprising: a base having a platform movably supported thereon and adapted to receive an investment container; a movable support mounted on the base for engaging and holding a pattern-supporting assembly; means for moving said support to carry the pattern to and from embedded position in the container; and means associated with said platform for imparting vibratory movement through the latter to the container supported thereon.

6. Apparatus for investing a casting pattern comprising a base having a platform movably supported thereon and adapted to receive an investment container; a movable support mounted on the base for engaging and holding a patternsupporting assembly; means for moving said support to carry the pattern to and from embedded position in the container; means carried by said support for imparting vibratory movement to the pattern; and means associated with said platform for imparting vibratory movement through the latter to the container supported thereon.

'1. Apparatus for investing a casting pattern comprising: a base having a platform movably supported thereon and adapted to receive an investment container; an arm pivotally supported at one end on the base; means mounted on the free end of said arm for receiving and holding a pattern-supporting assembly; means for moving said arm about its point of pivotal support, whereby to raise and lower said assembly relative to the container; and means associated with said platform for imparting vibratory movement through the latter to the container supported thereon.

8. Apparatus for investing a casting pattern comprising: a base, including a supporting platform having a plunger portion projecting upwardly from the surface thereof; an investment container adapted to be positioned on said platform, said container being open at its upper end, the lower end thereof being closed by an elastic cap adapted to engage over the plunger portion of said platform; a pattern-supporting sprue and a holder therefor, said holder being formed of an absorbent material; a movable support mounted on the base for engaging and holding said sprue holder; means for moving said support to carry the pattern to and from embedded position in the container; and means for applying downward pressure to the container after the pattern has become embedded therein, whereby to expel moisture from the mass of investment by forcing the plunger portion of said platform and the overlying portion of said cap upwardly into the container.

returned to inoperative posi- 9. Apparatus for investing a casting; pattern comprising: a baseprovided with a platform for supporting an investment container; an arm i pivotally supported at one end on the base; and means carried by the free end. of said arm for ,engaging and holding a pattern-supporting assembly, the free-end of said arm being oil-set upwardly to permit mounting of the pattern in axial alignment with the main portion of said arm, and said platform being arranged to sup- .U10. Apparatus for investing a casting pattern ing an investment container; an arm pivotally supported at one end on the base; means mounted on the free end of said arm for engaging and holding a pattern-supporting assembly; and

means for moving said arm about/its point of pivotal support, whereby to raise and lower said; assembly relative to the container, said means including a spring-actuated motor having a manually-operable wind-up device, a lifting cam, and means affording driving connection between said cam and the motor and motor 5:10.

wind-up device, said last mentioned means being arranged to move the cam to position for holding the assembly in elevated position when said wind-up device has completed the wind-up movement.

DAVID W. PHILLIPS. 

